1. What is Water Heater Sizing?

Water heater sizing is the process of determining the appropriate capacity of a water heater based on your household's hot water demands. Proper sizing ensures you have enough hot water when needed while maximizing energy efficiency.

2. How Does the Calculator Work?

The calculator uses the standard sizing formula:

Where:

• \( Flow Rate \) — Gallons per minute of hot water required
• \( Temperature Rise \) — Difference between incoming cold water temperature and desired hot water temperature
• \( 500 \) — Constant factor (1 gallon of water raised 1°F requires approximately 8.33 BTU, and 8.33 × 60 minutes = ~500)

Explanation: This formula calculates the BTU/hour requirement to heat water at a specific flow rate through a specified temperature rise.

3. Importance of Proper Sizing

Details: Correct water heater sizing is essential for energy efficiency, cost savings, and ensuring adequate hot water supply. An undersized unit will struggle to meet demand, while an oversized unit wastes energy and increases operating costs.

4. Using the Calculator

Tips: Measure your peak hot water flow rate in gallons per minute and determine the temperature rise needed (typically 60-70°F rise from groundwater temperature). For Canadian climates, consider colder incoming water temperatures in winter months.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical groundwater temperature in Canada?
A: Groundwater temperatures vary by region but typically range from 40-50°F (4-10°C), with colder temperatures in northern regions and winter months.

Q2: How do I calculate my peak flow rate?
A: Add the flow rates of all fixtures that might run simultaneously. Standard flow rates: shower (2.5 GPM), faucet (1.5 GPM), dishwasher (2-3 GPM), washing machine (2-4 GPM).

Q3: What temperature should hot water be set to?
A: Health Canada recommends 49°C (120°F) to prevent scalding while minimizing legionella risk. Some jurisdictions may require higher temperatures for commercial applications.

Q4: Should I consider recovery rate for tank water heaters?
A: Yes, for tank-type water heaters, both storage capacity and recovery rate (how quickly the tank reheats) are important factors in sizing.

Q5: Are there different considerations for tankless vs tank water heaters?
A: Yes, tankless water heaters are sized primarily based on flow rate and temperature rise, while tank water heaters consider both storage capacity and recovery rate.